Veterinary tooth extractor

ABSTRACT

A hand-held and operated instrument suitable for removal of a molar or premolar tooth of an animal, in this particular application, a horse. The device includes the combination of a unique forcep design which articulates via a threaded communication with a drive unit contained within a housing, by which the operator, from outside the mouth, may cause with substantial increase in advantage, the forcep to move in a direction opposite that of the drive housing unit which will then act as a counter-bearing surface upon the teeth or other aspects of the mouth immediately adjacent to the tooth to be extracted. Thus removing or lifting the tooth grasped by the forceps vertically from its socket.

BACKGROUND OF THE INVENTION

This invention relates to tooth extractors and more particularly to anovel tooth extractor which is designed to remove an equine cheek toothfrom within the animal's mouth. It is not uncommon for the need toremove a horse cheek tooth to arise. Frequently the reason being aprofound sinusitis/infection secondary to a diseased tooth. Heretofore,only the most diseased of teeth could be removed from within the mouthutilizing standard veterinary molar extractors, the force being providedsolely by the muscular strength of the operator. Due to the inability ofhorses to "open-wide" the lack of room within the mouth in which tooperate has precluded the removal of any molars or premolars that werestill tenaciously bound within the socket, by the above described means.The accepted method for removal of cheek teeth in this latter categoryis the performance of a sinusotomy (in the case of the upper arcade) orthe removal of a window of bone around the tooth root (in the case ofthe lower arcade) and subsequent repulsion of the tooth using a mailetdriven punch applied to the root end of the tooth and driving the toothout of its socket into the mouth. Thus prior to my invention there hasbeen no efficient means by which to extract moderately diseased ornearly normal cheek teeth without great stress being applied to theanimal in the performance of a tooth repulsion as described above.

SUMMARY

Accordingly, it is an object of the present invention to provide a toothextracting instrument specifically suited for extracting a molar orpremolar tooth from a horse, or other animal, wherein the instrument isrelatively easy to manipulate and maneuver with the hands of theoperator outside the mouth of the horse.

Another object of this invention is to provide a tooth extractinginstrument in which uniquely designed molar forceps may grasp a toothand by the action of two sets of articulating screw drives, or someother appropriate gear configuration, remove the tooth and rootcompletely from its socket. The housing in which the two drivemechanisms are contained functions as a counter-bearing surface withadjacent molar or premolar teeth or other aspects of the mouth where itmay find purchase.

In accordance with the present invention in a preferred embodiment shownthere is provided a pair of molar forceps uniquely designed toaccommodate the equine cheek tooth while grasping said tooth andmaintaining a low tolerance articulation with vertically orientedstationary screws which turn upon their axes outboard of the forcepheads. They in turn are driven by horizontally positioned worm screwsthat rotate upon their axes and are turned by the operator from outsidethe mouth. The vertical screws and horizontal worm screws are connectedvia a "wormgear". The ability of the operator to turn the screw drivesindependently of each other allows for small unequal changes inelevation on the medial and lateral aspects of the tooth in relation toits socket. This "rocking" motion coupled with the axial twist theoperator can produce by grasping and manipulating the handles of theforceps directly along with the tremendous mechanical advantage producedby the twin screw drive configuration allows the grasped tooth to beremoved from its socket. Other objects, advantages, and features of thepresent invention will become more apparent as the description proceedstaken in conjunction with the accompanying drawings in which:

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of the tooth extractor without forcep ordriveshaft handles illustrated.

FIG. 2 is a side elevation of the extractor in which the forcep headsare elevated above the housing assembly as they would be for placementupon a tooth;

FIG. 3 is a side elevation of the forcep shank handles and drive rodhandles;

FIG. 4 is a top plan view of the tension maintaining device;

FIG. 5 is a front end elevation of a forcep head unit;

FIG. 6 is a side elevation cutaway view of a forcep unit and crossbarassembly relative to the upper and lower molar arcades as in place foroperation.

Referring now to the drawings, in FIGS. 1-6 there is shown a toothextracting device in which the horizontally positioned drive rods 1 turnupon their axes in place with the threaded worm portion 14 articulatingwith the vertically oriented threads of the worm gear 3 on the bottomportion of the vertical drive rods 2 which have external threads androtate about a fixed portion of the housing 9. The threaded upperportion of the vertically positioned drive rod 2 articulates directlywith the extractor forcep heads 5. The forceps maintain their positionrelative to the housing assembly 9 via engagement fittings 8, shown tobe dovetail in design, which allow the forceps and housing assembly toslide in the vertical plane relative to each other. The housing assemblycrossbars 7 serve as the counter-bearing surfaces adjacent to thegrasped molar. Each crossbar 7, of which there are illustrated two, ischaracterized by one end possessing external threads 25, and theopposite end being smooth. The threaded recesses of the housing in whichthe threaded rod ends 25, reside, do not pass completely through thehousing component 9, and the rods are thus preferably firmly seated intotheir respective housing member on that side. Conversely, at the end ofeach rod opposite the threaded end, the rod is smooth and resides withina hole which communicates completely through the housing component 9.The tolerances in the vertical plane, between that portion of each rodthat slides relative to a housing member, are necessarily, preciselysmall, so as to prevent changes in angle between the housing components9, and the forcep dovetail articulations 8, thus preventing binding fromoccurring once a load is applied. Alternately, the tolerances betweencrossbar rod 7, and housing component 9, in the horizontal plane, are,where required, sufficiently large to accommodate the changes in anglefrom parallel between the housing members 9, that will occur as theforcep heads 5, and thus the housings 9, are opened and closed forplacement upon a tooth. The diameters of the rods are of sufficientmagnitude, based upon rod composition, to prevent any bending or twistonce a load is applied. A concave indentation 6 in the face of theforcep heads 5 increases the surface contact area with the grasped toothby accommodating the basic conformation of the equine cheek tooth. Thetruncated pyramidal shape of the forcep heads 5 allows for full 180degree contact between the female threads of the forcep heads 5 and themale threads of the upper portion of the drive rods 2 while maintaininga narrow enough tooth bearing surface so as to avoid overlappingadjacent teeth when engaged upon the tooth 4 to be extracted. Theforceps, housing assembly and drive gears are constructed of a metalsufficiently hard enough to maintain the desired tolerances understrain, through repeated uses over long periods of time. The lateralposition of the drive units allows that only the pivot region 10 of theforceps and the crossbars 7 need cross the space between the tablesurfaces of the upper and lower molar arcades, that space beinggenerally about one inch in height. This design takes particularadvantage of the general conformation of the equine mouth.

The external dovetails 8 sliding within the internal dovetail grooves ofthe housing assembly maintain the forceps in close opposition with thedrive units rods 2 as the forceps move up and down. The crossbars 7abutt the rostral and caudal adjacent teeth or other aspects of themouth to act as the counter-bearing surface which provides the purchaserequired to lift/pull the grasped tooth vertically from its socket. Theforcep heads 5 are placed upon the lateral and medial exposed aspects ofthe tooth to be removed while tension through the forcep shanks 11 ismaintained by the operator grasping together the forcep handles 17 aspictured in FIG. 3. The tension maintaining device 15 in FIG. 4 is thenset to allow the operator to let go of the entire assembly which willthen be suspended from the tooth of interest. The operator may then turnindependently of one another the drive rods 1 in a sequence mostconducive to disruption of the periodontal ligamentous attachmentbetween the tooth root and its socket. As the drive rods 1 rotate, theirworm threads 14 transfer their force to the vertical plane byarticulation with the worm gear 3 (which is not visible behind thethreaded portion of drive rod 1 in FIG. 2) on the lower portion of thevertical drive rod 2. This causes the vertical drive rod 2 to turn uponits axis in place with its horizontal external threads articulating withthe internal threads 12 of the forcep heads 5 in FIG. 2. This forces thedrive and housing assembly 9 upward until the crossbars 7 make contactwith adjacent teeth or other aspects of the mouth. At this point thedrive rods 1 and forcep handles 17 are manipulated by the operator untilthe tooth's attachment to its socket is overcome. In this manner aportion 26 of the tooth grasping means moves away from the crossbars 7which rest against the table surfaces of teeth adjacent to the toothwhich is being extracted as shown in FIG. 6. Thus depending on thelength of the tooth root, the tooth may be removed with the extractorpictured or said extractor removed and the tooth extracted withconventional forceps if not by hand.

The forcep shanks are controlled by the operator by grasping the handles17 which have a bend of approximately 80 degrees in order to make iteasier for the operator to handle the placement of the forcep heads 5upon the tooth to be extracted. This bend allows the operator's hand toremain below the mouth thus enhancing the operator's ability to seewithin the mouth. Once the forcep heads 5 are placed upon the tooth thehandles 17 are closed together as tight as necessary to ensure anadequate seating of the forcep teeth 20 as shown in FIG. 5 into thetooth. At that point a lock nut 16, or the like, is tightened down uponthe threaded rod 15 which acts to maintain the tension in the forcepshanks and thus upon the tooth through the forcep heads 5. The holes 30in the forcep handles 17 are of a diameter large enough to allow forchanges in angle from parallel between the two shanks as they arebrought closer together or moved farther apart and prevent binding ofthe rod 15. After the forceps are set in place the operator may thenturn the drive rods 1 by grasping the handles 18 and turning. Thehandles 18 slide within the drive rod 1 which allows the handles to beof sufficient length to fit comfortably in the operator's hand and alsoprovide mechanical advantage while avoiding contact or interference withthe opposite handle which is necessarily in close proximity due to thenarrowness of the mouth and thus the narrowness of the device itself.The teeth 20 of the forcep head 5 as shown in FIG. 5 are of a dimensionsubstantial enough and sharp enough to bite adequately into the surfaceof the tooth sufficiently to prevent slippage once a lifting force isapplied.

It is recognized that other combinations of screws, helical gears, orthe like could be utilized to provide the force necessary to actuate thedevice and that the prior explanation and accompanying drawings are butone representation of a basic idea whereby there is a 90 degree transferof force applied outboard of the forcep heads and thus not between theocclusal surfaces of the opposing molar arcades, the intent of which isto remove a tooth from within an animal's mouth.

I claim:
 1. A tooth extracting assembly having a tooth grasping means, apurchase means, means to displace a portion of said tooth grasping meansaway from said purchase means while extracting said tooth, and means tocause said tooth grasping means to grasp said tooth, said means to causebeing located substantially entirely beyond the area between occlusalsurfaces of molar arcades within a patient's mouth when said assembly ismounted therein.
 2. A tooth extracting assembly according to claim 1wherein said means to displace includes a gear mechanism.
 3. A toothextracting assembly having a tooth grasping means, a purchase means andmeans to displace a portion of said tooth grasping means away from saidpurchase means while extracting said tooth, wherein said means todisplace includes a gear mechanism.
 4. A method of extracting a toothcomprising a first step of grasping a medial and lateral surface of thetooth with a grasping means comprising means to cause said toothgrasping means to grasp said tooth, said means to cause being locatedsubstantially entirely beyond the area between occlusal surfaces ofmolar arcades within a patient's mouth a second step of actuating adisplacement means to displace a purchase means to a surface adjacent tothe grasped tooth wherein a portion of the grasping means is displacedaway from said purchase means, thus extracting the tooth.